FYI - How I run a Laptop (etc) through my headunit.

[Pernod]

For those of you that have been reading the Neon thread in 'Bodykits' then you will probably have had a bit of a giggle over the fact that I have scorched two fingers by grabbing the wrong end of my soldering iron!

As what I was working on at the time may be of use to some other people around the place, I thought I'd post some info up here :-)
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The aim of what I was doing was to enable me to plug in either a laptop or a MP3 Discman into my car for long haul trips, while still being able to use the CD changer day to day.

It would have been possible to do this by unplugging the headunit from the amp and plugging the other unit in, however lets face it - that's not very practical. So instead I went looking for a way to be able to plug the MP3 Discman straight into my headunit (so that I could still control volume, L&R channels etc via the headunit)

The answer was reasonably obvious - run it into the RCA input where my CD changer plugs into. This took a bit of playing, so I thought I'd share my findings incase anyone else decides to do anything similar... Heres the key things to think about: -

** In order to avoid 'interference', my CD Changer actually sends a powered signal to the headunit. From what I gather this is reasonably common amongst most headunit/changer combinations (If anyone wants the reason for them doing this, then I can explain this as well).
This actually made the job alot easier, as (in my case) the powered signal level from the CD changer is pretty close to the power output for headphones from other devices. This means that in theory I can plug in any device that is designed to run headphones (ie - almost anything) rather than only things with a line out device (which is what I had thought I would need)

** My CD Changer sends the sound via standard RCA leads, while sending control info via a separate cable. This means that even if the Changer RCA's aren't plugged in, the car will still 'think the changer is attached'. This means that I can plug in something different into these RCA inputs, and the CD changer will still 'think' it is playing the changer so will use any signal coming through the RCA inputs from any device.

After discovering this, I have found two ways to get it to work...

The simple way (and how I tested my ideas) was to place a double adaptor into each of the headunit RCA inputs, and then plug in BOTH the changer, and my Discman cables. Basically, when the discman isn't playing (or attached) it plays as normal. The issue comes when you go to play the discman, as it will still be playing the CD in the changer as well (as my headunit wont let you switch to the changer input unless there is a disc in the changer). To get around this I simply placed a disc in the changer with a 'blank' song (Made using a shareware program called GoldWave) and made it repeat this silence from the changer - hence the only sound the headunit gets is from the discman.

The harder way, but safer/easier to use (unless of course you burn fingers in the process :oops:).
I have made a new 'splitter' cable to replace the double adaptors. This new cable has a switch which makes it so that either the signal from the changer is used, OR (rather than the 'and' in the previous case), the discman/laptop signal is used. This means that with t he flick of a single switch, I can change back and forth between the CD changer and the Discman/Laptop - no having to worry about loading the 'blank' song in the changer etc. I can post pics of how I made this if anyone would find them useful?

It has made it a heap easier for us on longer trips, as we can just take 4-5 MP3 cds, or the laptop, and have all the music we need rather than needing a stack of CD's (and having to stuff around changing them all the time).

I hope this all makes some sort of sense??????

I'm not sure if anyone else has tried something similar (and I know some headunits already have a line in) or if anyone else has wanted to be able to plug other things into their headunit? But thought I'd post this anyway incase it was of interest/use.

Feel free to ask any questions that you want (I'm sure if I cant answer them, someone will be able to?). Or if you have any other Ideas on what I can try, then I would love to hear them ;-)

Shane

[Dogo]

u can buy a little box that does that. Takes multiple inputs and lets u choose one via a switch. Ive seen them for home stereo systems, but its all the same. multiple rca pairs in, 1 pair out.

But well done on making ur own. Id be interested to see the pics of how u made it, tho i wont be doing it.


Now, your next project is :

I need to get a coax digital signal into an optical digital signal. can u do that too ? :wink: Main problem is that the optical signal doesnt go thru one of the normal little suarish optical plugs, it has a coax-style plug, but is optical. bah !!

Good work ! Shame abt ur hands

[submersiblepotato]

I had the same idea for the MP3 laptop etc...

My pioneer head unit has a multi-pin connector at the back which is made for connecting to a stacker, however it also allows you to connect an auxillary rca input. I purchased the adapter (all 180 dollars of it) and installed it in the void beneath the headunit (behind the ashtray). I then ran some extended leads and mounted a pair of rca's in the passenger side blank beneath the handbrake, it looks like an optional accessory :)

Works well......

just thought i'd let you know...

Sub

[Pernod]

Well despite a couple of blistered fingers, I couldn't resist putting this in today :)

I have put the switch just below the cigarette lighter, and at this stage the extra RCA inputs are hiding behind the passengers foot panel.

[pr1mo]

Now, your next project is :

I need to get a coax digital signal into an optical digital signal. can u do that too ? :wink: Main problem is that the optical signal doesnt go thru one of the normal little suarish optical plugs, it has a coax-style plug, but is optical. bah !!



yeah that can be done dave. just goto jaycar (or speak to trav) they have these small box looking things which a coax goes in one end and a S/PIDF optical cord comes out the other (they have another unit for coverting the other way) read a review on em agges ago and the guy couldnt fault it. no audio quality loss etc etc they r around $40 and youll need a powerpack to run it too or maybe u could wire it to the car elec as i think they run off 12 volts :)


oh here i found it :)

http://www1.jaycar.com.au/productView.asp?ID=AA1720&CATID=&keywords=optical& SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=xxxxx xxxxx&Keyword2=xxxxxxxxxx&pageNumber=&priceMin=&pr iceMax=&SUBCATID=

cheers mike

[Pernod]

Nice work Primo - you beat me to it.
I have been having a hunt to work out how to make one, however the finaly conclusion was that it's just not worth it! At $40 the pre designed option wins hands down!

As far as getting an adaptor to go from the square optical type plugs to the coax style, I'm not sure where you would go over there. I know that you can get them here in NZ (the shope I use doesn't have a website though sorry) - the guys at jaycar should be able to offer some ideas

[Dogo]

small box looking things which a coax goes in one end and a S/PIDF optical cord comes out the other


that looks like just what i need... Thanks !

[deon_attard]

Wouldn't it have been easier just to buy a deck that plays MP3's?

[Pernod]

It may have been, but this had a grand cost of about $15 ;-) and it gives me alot more flexibility as I can run either the work laptop, my mp3 player, or (from later this week) we are getting a little 'shuttle' computer (http://www.microbytes.com/pages/sizecomparison.jpg) which will be able to be used for longer trips (with the use of an inverter).

Dogo, how did you get on with your coax-optical switch?

[Dogo]

its still on the 'todo' list :wink:

[JynX]

Yeah ive been planning to do a shuttle install in my car with a 7" in dash touchscreen for control. I can interface it with the new ecu to display live engine stats as well.

[Pernod]

the touch screen thing is rather new to me... how hard is it to do?

[JynX]

Depends on the OS you use, Windows is pretty much plug and play. I think the touchscreen sends the signal via serial. Input can be RGB or S-Video on some models.

[JynX]

http://www.xenarc.com/product/700ts.html somthing like this has a usb interface for the touchscreen.. even easier :)